Vinyl chloride has been determined in air by direct injection into a microwave-induced reduced pressure (4.7 Torr) helium plasma using the Cl(II) line at 4794.5 Å. Matrix effects due to the quenching properties of oxygen and competing reactions of the nitrogen and oxygen necessitate the use of a number of gas standards. The emission spectrum of vinyl chloride in a helium plasma, together with calibration curves using mixtures of vinyl chloride in helium and vinyl chloride in air are presented. The reduced pressure discharge can accept sample sizes at least as large as 100 μl without affecting stability. A detection limit of 390 ppm of vinyl chloride in air with a selectivity ratio of 300 as compared to methane has been obtained. This poor detection limit was due to the presence of air which quenches the Cl(II) emission.
ASJC Scopus subject areas
- Analytical Chemistry